SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e39070ffb6d6706043d0812d861ab39b0c7dd9fa1a0f92277ccaba5f8413913' 
  AND token = 'QHKmpBqzztStABalltC2+AjFi4J17/zJ8Zem+CDyp44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}